Currently, in a Long Term Evolution (LTE) system, an adaptive procedure for a physical downlink shared channel (PDSCH,) is as follows: User equipment (UE) estimates channel information used for measuring channel state information (CSI); the UE calculates a signal to interference plus noise ratio (SINR) by using the channel information and based on an optimal rank indication (RI) and/or a precoding matrix indication (PMI); and the UE obtains a corresponding channel quality indicator (CQI) according to the SINR, and reports a CQI value to a base station. The base station allocates a modulation and coding scheme (MCS) to the UE according to the CQI value reported by the UE and a network condition, where the MCS is used for indicating a modulation scheme and a coding scheme that are currently used by the PDSCH.
In a hotspot scenario, for example, in a relay scenario or an LTE hotspot improvements (LTE-Hi) scenario, UE requires a modulation scheme higher than 64 quadrature amplitude modulation (QAM). However, due to a limitation in the prior art, a maximum CQI value is 15, and a modulation scheme corresponding to the CQI value is 64QAM; as a result, the UE cannot select a modulation scheme higher than 64QAM, thereby affecting system performance. Similarly, a base station cannot allocate a modulation scheme higher than 64QAM to the UE.